powerpc/32: Remove unneccessary calculations in load_up_{fpu/altivec}

No need to re-read SPRN_THREAD, we can calculate thread address
from current (r2).

And remove a reload of value 1 into r4 as r4 is already 1.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/c04cce578b97a76a9e69a096698b1d89f721768a.1629276437.git.christophe.leroy@csgroup.eu

arch/powerpc/kernel/fpu.S

@@ -91,8 +91,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_VSX)
 	isync
 	/* enable use of FP after return */
 #ifdef CONFIG_PPC32
-	mfspr	r5,SPRN_SPRG_THREAD	/* current task's THREAD (phys) */
-	tovirt(r5, r5)
+	addi	r5,r2,THREAD
 	lwz	r4,THREAD_FPEXC_MODE(r5)
 	ori	r9,r9,MSR_FP		/* enable FP for current */
 	or	r9,r9,r4

arch/powerpc/kernel/vector.S

@@ -65,9 +65,8 @@ _GLOBAL(load_up_altivec)
 1:
 	/* enable use of VMX after return */
 #ifdef CONFIG_PPC32
-	mfspr	r5,SPRN_SPRG_THREAD		/* current task's THREAD (phys) */
+	addi	r5,r2,THREAD
 	oris	r9,r9,MSR_VEC@h
-	tovirt(r5, r5)
 #else
 	ld	r4,PACACURRENT(r13)
 	addi	r5,r4,THREAD		/* Get THREAD */
@@ -81,7 +80,6 @@ _GLOBAL(load_up_altivec)
 	li	r4,1
 	stb	r4,THREAD_LOAD_VEC(r5)
 	addi	r6,r5,THREAD_VRSTATE
-	li	r4,1
 	li	r10,VRSTATE_VSCR
 	stw	r4,THREAD_USED_VR(r5)
 	lvx	v0,r10,r6